Telephone-transmitter



Patented Apr. 25, I899.

P. c. BURNS. I TELEPHONE TRANSMITTER.

(Application filed Ian. 12, 1899.)

No Model.)

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PETER C. BURNS, OF CHICAGO, ILLINOIS.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 623,702, dated April 25, 1899.

Application filed January 12, 1899. Serial No. 701,945. (No model.)

ments in Telephone-Transmitters, of which the following is a specification.

My invention relates to certain improvements of a structural character in what are known as solid-back telephone-transmit-v ters which employ granular carbon in cooperative combination with the diaphragm as a variable contact medium.

My invention has for its object the provision of means for detachably and firmly holding the various parts of the transmitter intimately together in such a manner as to permit ready and convenient assemblage and detachment and separation of said parts. To accomplish this result, I provide screwthreaded connecting and holding bolts extended from the front or face plate or cover of the transmitter, perforations in the solid back of the transmitter, through which said bolts may pass, locking-nuts on said bolts which engage the said solid back and lock it to the face-plate or cover, with the diaphragm between them, and also perforations in the shell surrounding the solid back, through which the said bolts may pass,with lockingnuts on said bolts engaging the shell. In assembling the parts the bolts fixed on the faceplate are threaded through the perforations in the solid back, with the diaphragm between them, and the locking-nuts adjusted to engage against the solid back and hold it and the diaphragm firmly in position upon the face plate. Then the bolts are threaded through the perforations of the shell and other locking-nuts adjusted upon the bolts to engage said shell and hold it firmly in a position to inclose about the solid back and engage the face-plate or cover.

Reference may now be had to the accompanying drawings, in which Figure 1 is a central sectional view through a transmitter, showing the various parts held together in proper position. Fig. 2 is a view showing the various parts detached and in position to be connected together. Fig. 3 is a front view of the diaphragm, showing conducting-arms secured thereto. Fig. 4 is a detail view of the conducting-arms, the carbon electrode, the detachable connection, and the diaphragm shown separated.

The face-plate or cover is designated at A, having connecting-bolts A A extended therefrom, screw-threaded to receive two sets of locking .-.nuts, to be described. The solid back B, of insulating material,which contains and holds the granular material B is perforated near its edge at B B and the bolts A A pass through these perforations when the solid back B is adjusted in position. The locking-nuts E E are adjusted on the bolts A A when the solid back is in positionagainst the face-plate or cover A and screwed firmly against the rear face of said solid back to hold it firmly against the said face-plate or cover. The shell H, inclosing the solid back B, is also perforated at J, and the extended bolts A A are likewise threaded through these perforations, and the locking-nuts E E adjusted on said bolts and screwed against the shell to hold it firmly about the solid back B, with its annular edge in engagement with the annular edge of the faceplate or cover A, Fig. 1. By this means the various parts are held securely together. The diaphragm K, interposed between the solid back B and the face-plate or cover A, together with said faceplate and solid back, are all held and locked together by the bolts A A and the lockingnuts E E. The shell H is also held securely in position on the solid back and locked in position to inclose the solid back and join with the face-plate. It is obvious that by these means the parts are capable of convenient and ready assemblage and detachment or separation and when assembled are all securelybound and held together.

I also provide conducting-arms L L, held on the diaphragm K, which are connected by the detachable screw connection L with the carbon-plate electrode M, also held on the diaphragm K by said screw connection L The screw connection and said conductingarms electrically connect the carbon electrode M with the face-plate or cover A, as the ends of said arms bear upon said faceplate. The diaphragm is isolated by a circular peripheral ring of insulating material N.

ICO

Having thus described my invention, what I shell having perforations therein, through I claim as new therein, and desire to secure which the said bolts pass, and locking-nuts by Letters Patent, is on the bolts engaging against said shell and In a telephone-tramsniitter a face-plate, or holding it securely and tightly about the solid cover, bolts secured to and extended from said back and in joined connection with the facefaee-plate, a solid back piece, having perfoplate, or cover. rations therein through which the said bolts Signed by me, at Chicago, Cook county,lllipass, locking-nuts on said bolts engaging nois, this 9th day of January, 1899. against the solid back and holding it tightly PETER C. BURNS. and securely to the face-plate, or cover, a diaphragm held between said solid back and faceplate by the means aforesaid, an inclosing Witnesses:

CHAS. G. BULKLEY, L. M. BULKLEY. 

